A theoretical formalism to calculate the single crystal elastic constants for orthorhombic crystals from first principle calculations is described. This applied TiSi2 and we using a full potential linear muffin-tin orbital method local density approximation (LDA) generalized gradient (GGA). The calculated values compare favorably with recent experimental results. An expression bulk modulus along crystallographic axes of crystals, constants, has been derived. From this moduli are found be in...

The electronic structure and ground state properties of ${\mathrm{AlB}}_{2}$ type transition metal diborides ${\mathrm{TMB}}_{2}$ (TM=Sc, Ti, V, Cr, Mn, Fe, Y, Zr, Nb, Mo, Hf, Ta) have been calculated using the self consistent tight-binding linear muffin-tin orbital method. equilibrium volume, bulk moduli ${(B}_{0}),$ pressure derivative ${(B}_{0}^{\ensuremath{'}}),$ cohesive energy ${(E}_{\mathrm{coh}}),$ heat formation $(\ensuremath{\Delta}H),$ specific coefficient $(\ensuremath{\gamma})$...

Electronic band structure and optical properties of zinc monochalcogenides with zinc-blende- wurtzite-type structures were studied using the ab initio density functional method within local-density approximation (LDA), generalized-gradient approximation, $\mathrm{LDA}+U$ approaches. Calculations spectra have been performed for energy range $0--20\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, without including spin-orbit coupling. Reflectivity, absorption extinction coefficients, refractive index...

Structural phase stability, electronic structure, optical properties, and high-pressure behavior of polytypes ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ in three space group symmetries $I{2}_{1}3$, $Ia\overline{3}$, $R\overline{3}$ are studied by first-principles density-functional calculations. From structural optimization based on total energy calculations, lattice positional parameters have been established, which found to be good agreement with the corresponding experimental data except for...

The stability of MgH2 has been studied up to 20 GPa using density-functional total-energy calculations. At ambient pressure alpha-MgH2 takes a TiO2-rutile-type structure. is predicted transform into gamma-MgH2 at 0.39 GPa. calculated structural data for alpha- and are in very good agreement with experimental values. equilibrium the energy difference between these modifications small, as result both phases coexist certain volume field. Above 3.84 transforms beta-MgH2, consistent findings. Two...

The computational framework of this study is based on the local-spin-density approximation with first-principles full-potential linear muffin-tin orbital calculations including polarization (OP) correction. We have studied magnetic anisotropy for a series bilayer CuAu(I)-type materials such as $\mathrm{Fe}X,$ $\mathrm{Mn}X(X=\mathrm{N}\mathrm{i},\mathrm{P}\mathrm{d},\mathrm{P}\mathrm{t}),$ CoPt, NiPt, MnHg, and MnRh in ferromagnetic state using experimental structural parameters to...

We report on ab initio calculations of the optical properties lead chalcogenides PbS, PbSe, and PbTe performed with a relativistic full-potential linear muffin-tin orbital method within local density approximation. Our calculated spectra are in excellent agreement recent ellipsometry measurements. The origin peaks is discussed, as well effects increasing chalcogen atomic number. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 349–358,

$\mathrm{Sr}\mathrm{Mn}{\mathrm{O}}_{3}$ is a rare example of compound having both cubic (high-temperature) and hexagonal (low-temperature) perovskite polymorph. While the former built from corner-sharing $\mathrm{Mn}{\mathrm{O}}_{6}$ octahedra only, latter contains confacial bioctahedral ${\mathrm{Mn}}_{2}{\mathrm{O}}_{9}$ entities along $c$ axis. The electronic magnetic structures polymorphs are investigated by density functional theory. Both insulators at...

The structural stability of ${\mathrm{MgH}}_{2}$ has been studied up to $16\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ using a high-pressure synchrotron x-ray diffraction technique. Several pressure-induced phase transitions have identified in this pressure range. Owing the close similarity between $\ensuremath{\alpha}$ and $\ensuremath{\gamma}$ modifications form can be stabilized as metastable after release. experimentally observed transition sequence volume changes at points well bulk...

The chemical bonding, electronic structure, and optical properties of metal−organic framework-5 (MOF-5) were systematically investigated using ab initio density functional calculations. unit cell volume atomic positions optimized with the Perdew−Burke−Ernzerhof (PBE) leading to a good agreement between experimental theoretical equilibrium structural parameters. calculated bulk modulus indicates that MOF-5 is soft material. estimated band gap from state (DOS) calculation for about 3.4 eV,...

Exploiting earth-abundant and low-cost photocatalysts for high efficiency photocatalytic water splitting is of profound significance. Herein, we report an improved activity by P As substitution at the N-site in C2N monolayer using state-of-the-art hybrid density functional calculations. Our results show that band gap can be reduced increasing concentrations substitution, same time obtained value higher than free energy except with x = 0.333. This indicates these new compositions P/As...

Mg decoration enhanced H₂ binding energy in 2D-C₂N and found to be a promising storage medium for mobile applications.

The electronic-energy band structure, site and angular momentum decomposed density of states (DOS), charge-density contours for ferroelectric sodium nitrite have been calculated using an accurate full-potential linear muffin-tin orbital method. total DOS is found to be in good agreement with experimental x-ray-photoemission spectra. From the analysis, as well studies, we conclude that bonding between Na ${\mathrm{NO}}_{2}$ ionic entities bond covalently. polarized reflectivity spectra, a...

The magneto-optic (MO) Kerr and Faraday spectra for manganese pnictides are calculated using the all electron, relativistic, full-potential linear muffin-tin orbital method. amplitude of our found to be in good agreement with corresponding experimental spectra. Although MO property is a rather complicated function diagonal off-diagonal elements optical conductivity tensor, present theory nevertheless provides very practical insight about its origin these compounds. largest effect observed...

Global environmental issues, in addition to limited fossil fuel resources, are being addressed by quests search of efficient visible-light-driven water splitting catalysts for hydrogen production. The photocatalytic activities CdX/C2N (X = S, Se) heterostructures have been investigated here using hybrid density functional theory calculations. calculated band gaps CdS/C2N and CdSe/C2N 1.48 2.12 eV, respectively. These ideal gap values that make possible harvesting more visible light from the...

The electronic structure of the perovskite La$_{1-x}$Sr$_x$CoO$_3$ has been obtained as a function Sr substitution and volume from series generalized-gradient-corrected, full-potential, spin-density-functional band calculations. energetics different spin configurations are estimated using fixed-spin-moment (FSM) method. From total energy vs magnetic moment curve for LaCoO$_3$ ground state is found to be nonmagnetic with Co ions in low-spin (LS) state, result that consistent experimental...

The ground-state and excited-state properties of the perovskite ${\mathrm{LaMnO}}_{3},$ mother material colossal magnetoresistance manganites, are calculated based on generalized-gradient-corrected relativistic full-potential method. electronic structure, magnetism, energetics various spin configurations for ${\mathrm{LaMnO}}_{3}$ in ideal cubic structure experimentally observed distorted orthorhombic obtained. such as optical, magneto-optical, x-ray photoemission, bremsstrahlung isochromat,...

In order to understand the role of hole doping on electronic structure, phase stability and magnetic properties ${\mathrm{LaCoO}}_{3}$ generalized-gradient-corrected, relativistic first-principles full-potential density functional calculations have been performed for ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}$ as a function x, using supercell approach well virtual crystal approximation (VCA). It has shown that rhombohedral distortion is stabilizing nonmagnetic...

The electronic structure and optical properties of orthorhombic, monoclinic, rhombohedral (corundum type) modifications ZnSiO3, rhombohedral, tetragonal, cubic (spinel Zn2SiO4 have been studied using ab initio density functional theory calculations. calculated fundamental band gaps for the different polymorphs compounds are in range 2.22–4.18 eV. lowest conduction is well dispersive similar to that found transparent conducting oxides such as ZnO. This mainly contributed by Zn 4s electrons....

The electronic structure of the series perovskites $A\mathrm{Mn}{\mathrm{O}}_{3}$ $(A=\mathrm{Ca},\mathrm{Sr},\mathrm{Ba})$ is examined with aid density-functional calculations. A range possible crystal structures for each compound, and in case calculated lowest-energy that observed at low temperature. factors control variation alkaline-earth ion ${A}^{2+}$ are discussed. $\mathrm{Ca}\mathrm{Mn}{\mathrm{O}}_{3}$ consists corner-sharing octahedra but orthorhombically distorted consistent...